When tumor growth is recognized in the body, excision of the tumor mass by surgery is regarded as the therapy of choice. However, this approach, while producing very satisfactory results as a general measure, is effective only for patients with tumors at an early stage of development. For example, in the case of late-stage primary liver cancer having underlying cirrhosis (common in Africa and in some Asian countries), the prognosis for surgical excision or resection is relatively poor. Regardless of the developmental stage of the cancerous mass, therapy through excision is frequently undesirable due to the possibility of missing related growths metastasized to a remote site, the physical scarring left by frequently radical surgical technique, and the risks commonly associated with surgery of any type.
Therefore, it is desirable to develop an effective therapy for cancer at all stages of development. The high radiation dosages required for traditional radiotherapy usually results in cellular damage to normal tissue adjacent the tumor. Moreover, the high radiation dosage invariably inhibits the normal immunological functions of the cancer patient and causes other irreparable damage. Hence, while radiotherapy has its advantageous applications, it is not ideal. A preferred therapy is one that would involve the use of tumorphilic substances with radionuclides in which the substances accumulate in the tumor tissue by intravasation or by direct implantation into the tumor tissue. This approach provides more specific high radiation dosage at the tumor sites.